Hello, I would like to know why there is no Playbook for a priest or exorcist type of character, it seems absent in the book

Hello! There's a couple of things going on here.

First, it was a deliberate decision not to have "good magic" within the setting. Have a sort of divine, holy energy takes away from part of the mood and feeling. If you know there's some divine, godly authority on your side, the horror can be taken away a bit.

In addition, I wanted to avoid keeping it too culture-specific: to not be overtly christian, or jewish or the like. Even in a fantasy setting, it very often just ends up being "Christian, but not", and I wanted to make sure there was flexibility there. The decision here was to make it so the undead-turning tool could basically be "anything" to some extent. You might have a holy symbol with a soul bound to it, or a magical soul, or the like.

Finally, the Scholar was always intended as the sort of "priest class". In a lot of vampire media, the priest is one who fights with knowledge - they know about garlic, mythology, and the like. In the original novel, Van Helsing is an educated man of science, but this is often adapted. The Hugh Jackman Van Helsing movie has a gadgeteer priest, and there's lots of overlap between the exorcist archetype and characters like Hellboy's Professor Broom or Lovecraft's Doctor Armitage.